on first launch, when i choose 'connect', the old window is still there but unusable
Download TBB 3.0rc1. In my case it was 32-bit linux English. Unpack it, run it.
You'll get the "connect" or "configure" dialog page.
Choose 'connect'. A new page will pop up, which is the "bootstrapping Tor status bar" page.
But the old 'connect or configure' page remains open too, and there's a "quit" option still visible. If I click it, it doesn't quit. Eventually my Tor bootstraps, and then both windows do vanish ("ok, I guess it did quit"), but then a Tor Browser appears.
Seems like the smarter thing to do for usability would be to vanish the 'connect or configure' page once they've picked one and it's no longer needed.